The present invention concerns an improvement for a cavitation (cavitation phenomenon) generating device for generating a local negative pressure to a fluid passing through a pipe body and a fluid mixing device using the device described above.
As a preceding step of intensifying mixing and stirring of a fluid for promoting various types of reactions, it has been conducted so far to generate cavitation (cavitation phenomenon) in a fluid passing through a tube.
There are various cavitation generating means and, among them, means of using a guide vane formed by crossing aslant chordal edges of a pair of semi-elliptic blade disks and closing the chordal edges upstream of a crossing point by a triangular partition plate that bisects a transversal plane of the tube and securing the arcuate edges of a semi-elliptic blade disks to the inner wall of the tube to form a flow deflecting channel in the tube in a state of directing the partitioning edge of the partition plate of the guide vane to the upstream is disclosed in the specification and FIG. 3 to FIG. 4 of U.S. Pat. No. 5,474,749.
In the cavitation generating device described above, the fluid is accelerated by the crossing pair of the slanted blade disks while being rectified into two branched flows by the partition plate in the process where the fluid passes through the guide vane in the tube thereby being defected into swirling flows applied with a large centrifugal acceleration to generate cavitation to the fluid downstream of the guide vane. However, since the fluid passage of the flow deflecting channel has a large open area formed by the chordal edge downstream of the crossing point of one semi-elliptic blade disk and the chordal edge upstream of the crossing point of the other semi-elliptic blade disks, acceleration of the fluid undergoes inevitable limit.
Accordingly a first object of the present invention is to further improve the cavitation generating device described above and provide a device for generating cavitation at higher negative pressure by promoting acceleration of a fluid.
A second object of the present invention is to provide a liquid mixing device of a higher mixing efficiency by utilizing the cavitation generating device described above.
For attaining the foregoing first object, the present invention provides a cavitation generating device comprising a tube for feeding a fluid under pressure; and a guide vane in which chordal edges of a pair of semi-elliptic blade disks are crossed aslant, a space between chordal edges upstream of the crossing point is closed with a partition plate that bisects a transversal plane of the tube and arcuate edges of the pair of semi-elliptic blade disks are secured to the inner wall of the tube, wherein a fluid channel between the chordal edge downstream of the crossing point of one semi-elliptic blade disk and the chordal side edge upstream of the crossing point of the other semi-elliptic blade disk of the guide vane is partially closed by a restriction means such as a baffle plate. With a constitution described above, centrifugal acceleration is increased for the spiral fluid passing the guide vane in the tube by the restriction means for the fluid channel, to thereby generate cavitation of a higher negative pressure downstream of the guide vane of the tube.
Further, for attaining the second object, the fluid mixing device according to the present invention comprises a tube for feeding a fluid under pressure; a guide vane in which chordal edges of a pair of semi-elliptic blade disks are closed aslant, a space between the chordal edges upstream of the crossing point is crossed with a partition plate that bisects a transversal plane of the tube, a fluid channel between the chordal edge downstream of the crossing point of one semi-elliptic blade disk and the chordal edge upstream of the crossing point of the other semi-elliptic blade disk is partially crossed by a restriction means such as a baffle plate and the arcuate side edges of the pair of semi-elliptic blade disks are secured to the inner wall of the tube; and a plurality of protrusion protruded radially from the inner circumferential wall surface downstream of the tube of the guide vane.
This constitution can remarkably promote mixing-stirring of a fluid, and can provide extremely high effect for various types of reaction and processings.
By shaping the protrusion downstream of the guide vane as a tapered protrusion of a convexly curved configuration, fibrous objects, if mixed in the fluid, do not cause entanglement to facilitate maintenance.
Further, the restriction means for the fluid channel of the guide vane may be preferably a plate integrated with the partition plate that bisects the transversal plane of the tube, or it may has a constitution that the chordal edges downstream of the crossing point of the semi-elliptic blade disk are bent or curved partially or entirely toward the restricted flow channel.